Question

span 【span】n.全长The average life span of people has increased considerably since the 19th century.人类的平均寿命自十九世纪以来已经大幅度地增加了。

Accepted Answer

[spæn] 
spanthe distance or interval between two points
Any distance between two things is called a span. These end points can be physical, like the span of a rope between two trees, or they can be more abstract, such as the span of time between five and six o'clock.
Span comes from the Old English spann, the width of the stretched-out hand, measured from thumb to little finger. It came to refer to various other measurements, such as the distance across an arch. The first reference to a length of time came in the late 16th century, and the phrase "attention span" first appeared in 1922 (as "span of attention").
All forms of 'span' will appear on average once every 608 pages.span

Front	span
Pron	[spæn]
Back	【span】 n.全长 The average life span of people has increased considerably since the 19th century. 人类的平均寿命自十九世纪以来已经大幅度地增加了。
Vocab	spanthe distance or interval between two points Any distance between two things is called a span. These end points can be physical, like the span of a rope between two trees, or they can be more abstract, such as the span of time between five and six o'clock. Span comes from the Old English spann, the width of the stretched-out hand, measured from thumb to little finger. It came to refer to various other measurements, such as the distance across an arch. The first reference to a length of time came in the late 16th century, and the phrase "attention span" first appeared in 1922 (as "span of attention"). All forms of 'span' will appear on average once every 608 pages. span

Span Distance Average Points Time Spæn N.全长 Life